Process for preparing dimethano-naphthalene



Dec. 31, 1963 G. H. RlEssER PRocEss FOR PREPARING DIMETHANONAPHTHALENE Filed Dec. 50. 1960 INVENTOR:

GREGOR H. RlEssER HIS AGENT United States Patent O 3,116,339 PRGCESS FSR PREPARING DIMETHANG- NAPHTHALENE Gregor H. Riesser, Pasadena, Tex., assignor to Shell Gil Company, New Yaris, NAL, a corporation of Delaware Filed Dec. 30, 1960, Ser. No. 79,838 8 Claims. (Qi. 2.60-667) This invention relates to the preparation of certain polycyclic hydrocarbons. More particularly, it relates to the preparation of hydrocarbons useful as chemical intermediates and also useful for the preparation of high energy fuel compositions.

in order to increase the range of volume-limited jet aircraft and the like, a fuel with a high heat of combustion both on a volume and on a weight basis would be highly desirable. Aromatic hydrocarbons are regarded as undesirable in such fuels as major constituents since they have such low heats of combustion per unit of weight and also because of their relatively poor burning qualities. Paran hydrocarbons which have not been modified are generally excluded as major fuel components because of their low density and hence their low heat of combustion per unit volume. Alkylmonocyclanes are somewhat better than paraiiins but become more like parafiins with the addition of alkyl side chains of suicient length to bring them into a suitable boiling range. Olens (especially straight chain oleiins) are undesirable because of their instability, although some cyclic olefin structures may merit consideration when inhibited against oxidation or when modified by the presence of relatively stable hydrocarbon structures.

Due to these exclusion factors, it is necessary to regard for primary consideration a certain group of hydrocarbons containing at least 2 carbocyclic rings. The rings may have no carbon atoms in common, or pairs of rings may share one, two, three or more carbon atoms which may be connected directly together or may be separated by one or more carbon atoms. Alkyl groups may be attached to the rings at various points so as to provide a suitable molecular weight and boiling point.

While it is true that many petroleum refinery hydrocarbon streams may contain minor amounts of desirable hydrocarbons in admixture with others of less desirable structures, it is also evident, from the lack of satisfactory fuels of high heat of combustion derived from petroleum sources by ordinary refinery practices, that the proportion of more desirable constituents is not sufficient to produce a desired product. For example, it is known that numerous petroleum refinery streams contain varying amounts of aromatics and among these are sources containing polycyclic aromatics. These streams can be hydrogenated in order to obtain improved fuel types containing poiycyclic naphthenes. Without extensive processing, however, it is difiicult and usually impossible by the use of previously known methods to obtain satisfactory fuels of high heat of combustion on both a weight and volume basis since these streams normally contain substantial proportions of types of hydrocarbons having reduced heating value either per unit volume or per unit weight.

Processes are available for the condensation of acetylene with cyclopentadiene to obtain polycyclic aromatic structures containing bicycloheptadiene as an essential and substantial component. In the course of this reaction a number of side reactions occur which heretofore have been regarded as largely undesirable since the principal objective was to obtain `the bicycloheptadiene for use as a chemical intermediate. Several of the by-products so obtained in minor amounts were dirnethanonaphthalene and trimethanoanthracene as well as dicyclopentadiene.

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Steps were taken to minimize the formation of these formaliy undesirable by-products so as to maximize the yield of bicycloheptadiene. However, the structure of trimethanoanthracene and dimethanonaphthalene are such as to suggest the possibility of eventually hydrogenating these materials to obtain their saturated analogs, namely, trimethanoperhydroanthracene and dimethanodecalin since calculations have shown that these particular species and closely related short chain alkyl substituted homologs thereof have extremely high heat of combustion on either a weight of volume basis.

It is an object of this invention to produce polymethanopolycyclic hydrocarbons. It is another object of this invention to produce a hydrocarbon composition containing a substantial proportion of dimethanonaphthalene at the expense of the production of bicycloheptadiene. it is a further object of the invention to provide compositions useful for high energy fuel compositions. lt is a particular object of the invention to provide for the suppression of undesirable by-iroduct formation in the preparation of dimethanonaphthalene and in the production of trimethanoanthracene. Other objects will become apparent during the following description of the invention.

The FIGURE illustrates apparatus suitable for carrying out the process of the invention.

Now, in accordance with the present invention, a process is provided for the production of compositions containing a substantial amount of dirnethanonaphthalene which comprises introducing cyclopentadiene and bicyclo- (2,2,l)2,5heptadiene in mol ratios between about 0.25 and 5.0 into a reactor at temperatures between 275 and 365 C. and at pressures between about 75 and about 200 p.s.i.g. for a reaction time between about 5 and l5 minutes, whereby a reaction product containing substantial proportions of dimethanonaphthalene is formed.

For some purposes the production of certain by-products and reversion products is undesirable in this process. For example, the process as just described results in a certain reversion of the heptadiene to acetylene and cyclopentadiene. This side reaction may be depressed by injecting acetylene in the mixture being introduced into the reactor as long as the mol ratio of acetylene to cyclopentadiene is maintained between about 0.1 and 3.0, preferably 0.52.0. By this means the reversion of heptadiene in the reactor to acetylene and cyclopentadiene is materially depressed, the principal product then being dirnethanonaphthalene and the proportion of acetylene appearing in the reaction product being essentially no more than and often less than that originally introduced into the reactor.

In accordance with one aspect of the present invention, the process may be operated for the production of dimethanonaphthalene to the virtual exclusion of the production of the bicycloheptadiene by restriction of the mol ratio of cyclopentadiene to heptadiene to between about 0.50 and 1.0. Under these circumstances, the principal desired product found in the reaction product is dimethanonaphthalene to the virtual exclusion of any increase in the heptadiene content relative to the amount of heptadiene originally introduced into the reactor. If, however, in the process it is desirable to produce dimethanonaphthalene and bicycloheptadiene, then it is possible to increase the mol ratio of cyclopentadiene to heptadiene to preferably between about 1.0 and 3.0 whereby substantial proportions of both bicycloheptadiene and dimethanonaphthalene are produced in the reaction product.

In still another aspect of this invention, a process is provided for the product-ion of high energy fuel which capitaiizes upon the side reactions resulting in the formation of tiimethanoanthracene at .the same .time that diniethanonaphthalene is being produced. In this process, the steps previously described are carried out, acetylene and any cyclophentadiene are then separated from the reactor product and the remaining reaction product is thereafter hydrogenated to produce a high energy fuel containing both dimethanodecalins and trimethanoperhydroanthracene.

Another `aspect of the invention comprises `a refinement of the basic process which suppresses the formation of undesirable polymeric materials. In the nature of the reaction as described above, not only are the previously described reaction products `formed but also polymeric substances of relatively higher molecular weight yand of somewhat indeterminate structure are formed. For most purposes it is undesirable to allow these to remain in the reaction product, and for many other purposes it is highly desirable to suppress polymer formation since this polymer is always produced at the expense of additional production of desired reaction components. Consequently, in accordance with this aspect of the invention, the reaction product emerging from the reactor and comprising dimethanonaphthalene with or without bicycloheptadiene and contaminated with polymer formed during the reaction, is subjected to distillation whereby any acetylene formed in the reaction or passing therethrough is volatiliZed and recycled to acetylene storage and any cyclopentadiene present in the reaction product is likewise volatilized and recycled to cyclopentadiene storage. In the distillation, further, the desirable intermediate boiling components including essentially dimethanonaphthalene are taken off as an intermediate boiling cut and a bottoms product high in polymer content remains.

In accordance with one additional feature of the process of this invention, it is possible to effect increased production of polymethanopolycyclic hydrocarbons which heretofore have been regarded as undesirable by-products of the known reaction. Since polymethanopolycycli hydrocarbons, including especially trimethanoanthracene and the like, have exceedingly high heating value it may, at times, be highly desirable to maximize their production at fthe expense of other components of the reaction product. These higher polycyclic materials are normally produced by further condensation of the intermediates (the latter having heretofore been desired primarily) and steps have always been ytaken to minimize their production by the use of relatively restricted temperatures and the use of the shortest possible reaction times. However, the process of this invention can be adjusted for maximizing production of polymethanopolycyclic hydrocarbons having more methane rings and/or more condensed rings by following the specified reaction time of -15 minutes by a further heating period of 5 6() minutes either at the same or a higher temperature.

The process of the invention will be better understood by reference to the figure which includes -apparatus suitable for carrying out the basic invention as well as the various optional and alternative aspects thereof. In the basic process, cyclopentadiene and bicyclo-(2,2,1)2,5 heptadiene are taken from storage sources 1 and 2, respectively, and sent by means of lines 3 and 4 to line 5 for introduction into preheater 6. In this short preheater section, the mixture of components is rapidly raised in temperature to approximately the reaction temperature, which is between about 275 and 365 C. The preheated mixture is then led by means of line 7 into the pipeline reactor 8, the pressure being adjusted, by means not shown, to between about 75 and 200 p.s.i.g. at the reaction temperature, the size and length of the pipeline reactor is adjusted for the volume of feed so as to 'maintain a resisdence time in the reactor of between 5 and l5 minutes for the initial heating period. The mol ratio of cyclopentadiene to heptadiene is maintained between about 0.25 and 5.0.

In the reaction just described, it is not necessary to inject acetylene; however, injection of acetylene will be referred to hereinafter. AFollowing 4the designated reaction period in pipeline reactor v2?, the reaction mixture is led by means of line 9 to a fractionating zone such as fractionating column 10. In this fractionating Zone, heated by means of heater l1, t-he reaction product is suitably separated into an overhead including acetylene formed in or injected into the pipeline reactor, which is recycled by means of line 12 to acetylene storage tank i3 or by means of lines 12 and tank 13 to the pipeline reactor 3. Any cyclopentadiene remaining in the reaction product may be recycled to cyclopentadiene storage area 1 orl by means of line 14 or by means of lines 14 and 15 to the pipeline reactor y8. An intermediate cut comprising essentially the desired methanopolycyclic hydrocarbons, specifically dimethanonaphthalene, is taken from an intermediate position on the column by means of line i6 to dimethano storage area 17. Polymer which may be formed in varying amounts in the pipeline reactor zone exits from the bottom portion of the fractionator tower by means of line 18 for discard. If the intermediate cut of the reaction product is to be converted to a high energy liquid fuel, it may be conducted by a preselected line l from an intermediate position on fractionating column lli) to a hydrogenation zone i9. Catalyst and hydrogen are added to the hydrogenation zone from sources 26 and 2l and hydrogenation of the product is effected under conditions known to experts in the art of hydrogenation. In this hydrogenation, it is preferred that an essentially saturated product be produced although partial hydrogenation of the product may be performed if so desired. The reaction mixture from the hydrogenation zone I9 is conducted by means of line 22 to a fractionat-in-g column 23 heated by means of heater 24. This column is for the purpose of hashing off any gas formed in the preceding steps together with any excess hydrogen, leaving the high energy liquid fuel which may be directly transmitted by means of line 25 to a storage area 26. This hydrogenated product, as intimated hereinbefore, comprises essentially substantial proportions of dimethanodecalin together with hydrogenated by-products of higher molecular weight such as trimethanoperhydroanthracene and the like.

In the event that yacetylene is to be injected into the initial reaction mixture, this may be done by passing acetylene from storage area 13 by means of line 5 to the preheater 6. Any acetylene recovered, such as from the top of fractionating column 10, may be utilized to decrease the `amount of acetylene drawn from storage source 13.

It will be seen that the principal accomplishment of the basic process of the present invention is the production of reaction products containing substantial proportions of dimethanonaphthalene and minimum amounts of the bicycloheptadiene. Prior art processes have involved the reaction of acetylene with cyclopentadiene, no bicycloheptadiene being injected into the system at the start of the condensation reaction.

The following data illustrate the results obtained by these prior art processes. It will be seen by Table I that a substantial proportion of the cyclopentadiene was converted to bicycloheptadiene with only about 3-9% of Athe converted product being dimethanonaphthalene.

Trimethanoanthracene was produced according to the j processes of the present invention only in fractional proportions.

In the tables which follow, the following abbreviations will be employed:

CPD Cyclopentadiene. C2H2 Acetylene.

BCH Bicycloheptadiene. CHT Cycloheptatriene. DMN Dimethanonaphthalene. TMA Trimethanoanthracene.

TABLE I C2H2/CPD, Res. Percent rn. conversion of CPD to- Polymer Run No. Temp. Press. Mole Time (percent C.) (p.s.i.a.) Ratio (min.) WJ

BCH CHT DMN TMA n Products other than BCH, CHT, DMN, CPD, and C2H2. b Not determined.

According to Table I, it will be seen that the object of the present invention is not accomplished by utilizing the prior art process in that large amounts of bicycloheptatriene are produced and that only insignificant amounts of either dimethanonaphthalene or of trimethanoanthracene are found in the reaction products.

In order to obtain a reaction product containing substantial proportions of dirnethanonaphthalene and, if desired, substantial amounts of trimethanoanthracene, the process of the present invention in its most simple form was employed. Table II illustrates the results obtained. According to Table II, it will be seen that the starting mixture injected into the pipeline reactor comprised of cyclopentadiene and bicycloheptadiene in mol ratios varying from about 0.33 to about 3.00. Essentially the same temperature, pressure and residence times were utilized as were employed in the prior art process described in Table I. However, due to the starting7 materials utilized, it will be seen according to Table II that the reaction product contains from 16 to over 43% of dimethanonaphthalene and that appreciable amounts of trimethanoanthracene were formed in amounts up to about 19%.

acetylene was actually .consumed in the process. The injection of acetylene into the starting reaction mixture together with cyclopentadiene and the bicycloheptadiene, however, resulted not only in substantial proportions of dimethanonaplithalene being formed but also resulted in suppression of side reactions such as reversion of the heptadiene to acetylene or the formation of appreciable amounts of trimethanoanthracene. Moreover, the production of polymer was minimized in a number of instances, the amount of polymer being restricted by the use of the relatively shorter residence times. Thus it is indicated according to the data given in Table III, as well as in Table II, that conditions within the generic aspects of this invention may be selected to obtain products in which dimethanonaphthalene predominates or products wherein dimethanonaphthalene is :modified by the presence of appreciable amounts of trimethanoanthracene and, further, that polymer make may be suppressed by utilizing relatively short reaction time.

The following examples illustrate further aspects of the invention particularly insofar as variation in ratios of acetylene to cyclopentadiene and of cyclopentadiene TABLE II CPD/BCH Res. Percent m. conversion of BCH to- Polymer Run No. Temp. Press. (Mole Time (percent C.) (p.s.i.a.) Ratio) (min.) w.)

DMN TMA C2H2 CHT 340 80 0.33 6 16. 4 0.8 14. 5 0.9 4. 9 320 80 1.0 12 33. 6 3.8 7. 2 0. 4 10. 7 320 100 2.0 9 43. 5 9. 7 5. 0 0.5 18. 2 340 80 3.0 G 38. 5 7.0 G. G 0.7 15.9

For many purposes, it is desirable to minimize reto bicycloheptadiene are concerned, the reaction comversion of bicycloheptadieue and other by-product reactions. This was eiiected by injection of minor amounts of acetylene into the reaction mixture as it entered the pipeline reactor. Results of typical experiments utilizing ponents introduced into the reactor (see zero time) being acetylene, cyclopentadiene and bicycloheptadiene.

Example I this alternative are given in Table III. Four runs were performed, holding the cyclopenta- TABLE III C2H2/CPD CPD/BCH Res. Percent m. conversion of BCH to- Polymer Run Temp. Press. (Mole 1(Molr (Time) (perrent No C. .s.i.a. Ratio atio min. i (p D MN TMA C2H2 CHT 300 0.5 0.5 15 15.4 0.4 0 1.6 2.6 300 0. 25 2. 0 30 47. 0 5. 8 e (48) 2. 8 12. 8 330 (50 0. 5 0. 5 9 16. 6 0. 7 5. 6 7. 3 5. l 330 100 0. 5 0. 5 18 24. 2 5. 9 4. 2 12. 2 10. 2 330 100 0. 25 2. 0 9 48. 7 7. 4 a (57. 7) 7. 2 13.9

Acctylcne consumed by reaction with CPD. b Products other than C2H2, CPD, BCH, CHT, and DMN.

It will be seen according to Table III that this prediene to bicycloheptadiene ratio constant at 0.5, the proferred version of the process of the present invention results in the production of substantial amounts of dimethanonaphthalene and the virtual suppression of the reversion of bicycloheptadiene. In fact, in a number of portion of acetylene to cyclopentadiene being varied. It will be seen that substantial proportions of dimethanonaphthalene were produced in each case, the higher proportions being produced with lower ratios of acetylene the experiments explained by the footnote Table III, present in the starting mixture.

T lvIA DMN CHT

BCI-I Reactor Products (moles/hour) CPD Temp., Press., Time C p.s.i.a.. (hrs.)

Run N0.

of Vdimetlianonaphthalene were formed in this process under the various conditions used.

Example Il Another rset of runs was made in which the ratio of Reactor Products (moles/hour) TLIA DL'IN CHT BCH

CPD

l. 2 033 0 4. nu 0 010903 6 0 0 000740531 Time (hrs.)

Run No. Temp., Press.,

C p si a cyclopentadiene to bicyoloheptadiene was held constant at 0.67 While the ratio of acetylene lto cyclopentadiene was varied from .33 to 3.0 and the temperature and pressure were varied as well. It will be seen from the data that substantial lamounts of 4dimetliaruonaphthalene wene produced in each oase, maximum amounts being formed Where the ratio of acetylene was lowest.

0 u A ,l B T 3 9 0 N 3 0 3 .l 5 7 G L m D w 0 S 0 0 0 1m T S 4 0 0 0 0 1 i m I C S ne u OMCT.. M 1% H 0404 4 P B .m C 0 0 a 070 03 C D 070 09 C 350500 2 3008er/ H 315050 2 C 0 0 5 C) 1 2 1 n .uw 0 0 0 h T( y 0 0 0 .a 5 5 5 S 1 1 1 S1 W5 Pu. y 0 0 0 4 2 4. WC 3 3 3 n e0 T n n 0 N n u n R 3 4 5 2 2 2 creasing with an increasing ratio fot cyolopentadiene to bicycloheptadiene.

Example III lA set of runs was made in which the ratio of Iacetylene 0 8 0 3 5 oo A 0 0 0 T 7 4 5 0 N 7 3 5 3 3 5 0 7 m m w m 1 2 3 6 e l 1 1 4 l T 0 0 0 1 O I m TI C S t C n 3 0 4 w 00050501 O H 07070807 r. C L0.l0.10.10. P B r O 1m 2 9 8 a 0908030 C D 0308040 R P 10.92.0.31:0 C

3059 2 0 2 31600009 H 32030401 2 0.0.00. LOL0 C 0 0 0 4 01./ 2 2 2 1 mm 0 .0 .0 .0 .l T@ 0 0 0 0 .a 5 5 5 5 S 1 1 1 l S1 mQ. Pp y 0 0 0 0 0 0 o 4 D. 3 3 3 3 mC CO T l 0 N m m m m n u n m m R m m 6 7 8 9 2 2 2 2 to cyolopentadiene was held -to a constant figure of 0:17 Example V A set of lruns was made holding the ratios of acetylene While the ratio of cyolopentadiene to bicycloheptadiene was varied from .Z to 3 with slight variation in temperature and pressure,

otter to the bicycloheptato cyclopentadiene and of `the l It will be seen that large amounts diene constant while varying the temperatures and pres- 9 sures. It Will :be seen that the reaction products all contained substantial amounts of the desired product, namely dimethanonaphthalene.

10 125 and about 175 p.s.i.g. for a reaction time between about 6 and about 12 minutes, and separating dimethanonaphthalene and an amount of the heptadiene sul Reactor Products (moles/hour) Run No. Temp., Press., Time C. p.s.i.a. (hrs.)

C2H2 CPD BCH CHT DMN TMA Example VI Further runs were mlade employing a variety of ratios of acetylene to cyclopentadiene with the results given below.

stantially greater than that introduced from the reaction product.

5. The process for the production of high energy fuel compositions vwhich comprises introducing cyclopentadi- Reactor Products (moles/hour) Run No. Temp., Press., Time C. p.s.i.a. (hrs.)

C2H2 CPD BCH CHT DMN TMA I claim as my invention:

1. The process for preparing dimethanonaphthalene which comprises introducing cyclopentadiene and bicyclo- (2,2,1)-2.,5heptadiene in mol ratios between 0.25 and 5.0 into a reactor at temperatures between about 275 and about 365 C. and at pressures between labout 75 and about 200 p.s.i.g. for a `reaction time between about 5 and about 15 minutes whereby a reaction product oontaining substantial proportions of dimethanonaphthalene i-s formed. t

2. The process for preparing dimethanonapthalene which comprises introducing cyolopentadiene, acetylene and bicyolo( 2,2,1)2,5heptadiene, the mol ratio of cyclopentadiene -to the heptadiene being between about 0.35 and about 5 'and the mol ratio of 'acetylene to cyolopentadiene lbetween about 0.1 and 2.0 into a reactor at temperatures between Iabout 275 land about 365 C. and at pressures between `about 75 and about 200 p.s.i.g. for a reaction time between about 5 land about 15 minutes whereby a reaction product containing substantial proportions of `dirnethanonlapthalene is formed.

3. Tlhe process for preparing dimethanonaphthalene which comprises introducing cyclopentadiene, acetylene and bicyclo-(2,2,1)2,5-heptadiene, the mol ratio of cyclopentadiene to the heptadiene `being between Iabout 01.50 and about 1.0 and the mol ratio of acetylene to cyclopentadiene between about 0.5 tand about 2.0 into a reactor at temperatures rbetween about 300 and 350 C. and at a pressure between about 125 and about 175 p.s.i.g. for a reaction time between yabout 6 and about 12 minutes and separating dirneth'anonaphthalene from' the reaction product.

4. The process for the preparation of substantial proportions of dimetharronaphthalene `and bicyclo-(2,2,1) 2,5-heptadiene which comprises introducing cyclopentadiene and bicycle-(2,2,1)2,5heptadiene in a mol ratio of between about 1.0 and about 3 and acetylene, the mol ratio of acetylene to cyclopentadiene being between about 0.10 and about 3.0, into a reactor at temperatures between about 300 and 350 C. and at a pressure between about ene and bicyclo-(2,2,1)2,5heptadiene in a mol ratio between abont 0.5 and about 1.0 into a reactor at temperatures between about 300 and about 350 C. and at pressures between about and 175 p.s.i.g. for a reaction time between kabout 5 and l5 minutes, separating acetylene and cyclopentadiene by-products from the reaction product and hydrogenating the remaining reaction product whereby a h-igh energy fuel composition is obtained.

`6. The process Afor the production of high energy fuel compositions which comprises introducing cyclopentadiene and `bicycle-(2,2,1)-2,5heptadiene in a mol ratio between about 0.5 land about 1.0 into a reactor at temperature between about 300 and about 350 C. and at pressures between about 125 and 175 psig. for a reaction time between about 5 and 15 minutes, separating acetylene, cyclopentadiene and polymer from the reactor product, recycling at least substantial portions of these to the reactor and hydrogenating the remaining portion off the reactor product to form a high energy fuel.

7. A process according to claim 1 wherein the initial reaction period of 5-15 minutes is followed lby la second heating period to a total about one hour heating time, the second heating period being at a temperature between about 275 and about 450 C.

8. A process according to claim 1 wherein the reaction product is subjected to fractional distillation to separately recover yacetylene and cyclopelntadiene, an intermediate *boiling cut comprising dimethanonaphthalene and a bottoms polymeric product, and recycling at least a portion of each of the acetylene, cyclopentadiene and polymeric bottoms product to the reactor.

References Cited in the le of this patent UNITED STATES PATENTS 2,754,337 Chirtel July 10, 1956 2,765,617 Gluesenkamp et al. Oct. 9, 1956 FOREIGN PATENTS 528,057 Belgium Apr. 30, 1954 

1. THE PROCESS FOR PREPARING DIMETHANONAPHTHALENE WHICH COMPRISES INTRODUCING CYCLOPENTADIENE AND BICYCLO(2,2,1)-2,5-HEPTADIENE IN MOL RATIOS BETWEEN 0.25 AND 5.0 INTO A REACTOR AT TEMPERATURES BETWEEN ABOUT 275 AND ABOUT 365*C. AND AT PRESSURES BETWEEN ABOUT 75 AND ABOUT 200 P.S.I.G. FOR A REACTION TIME BETWEEN ABOUT 5 AND ABOUT 15 MINUTES WHEREBY A REACTION PRODUCT CONTAINING SUBSTANTIAL PROPORTIONS OF DIMENTHANONAPHTHALENE IS FORMED. 